CVE-2021-39191
published 2021-09-03CVE-2021-39191: mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating…
PriorityP431medium6.1CVSS 3.1
AVNACLPRNUIRSCCLILAN
EPSS
1.75%
75.3th percentile
mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | libapache2-mod-auth-openidc | < libapache2-mod-auth-openidc 2.4.9.4-1 (bookworm) | libapache2-mod-auth-openidc 2.4.9.4-1 (bookworm) |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| msrc | cbl2_mod_auth_openidc_2.4.14.2-1_on_cbl_mariner_2.0 | — | — |
| openidc | mod_auth_openidc | < 2.4.9.4 | 2.4.9.4 |
| zmartzone | mod_auth_openidc | — | — |
CVSS provenance
nvdv3.16.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
nvdv2.05.8MEDIUMAV:N/AC:M/Au:N/C:P/I:P/A:N
osv6.1MEDIUM
vendor_msrc6.1MEDIUM
vendor_debian4.7MEDIUM
vendor_redhat4.7MEDIUM
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OSV
CVE-2021-39191: mod_auth_openidc is an authentication/authorization module for the Apache 2
osv·2021-09-03·CVSS 6.1
CVE-2021-39191 [MEDIUM] CVE-2021-39191: mod_auth_openidc is an authentication/authorization module for the Apache 2
mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.
Microsoft
URL Redirection to Untrusted Site ('Open Redirect') in mod_auth_openidc
vendor_msrc·2021-09-14·CVSS 6.1
CVE-2021-39191 [MEDIUM] CWE-601 URL Redirection to Untrusted Site ('Open Redirect') in mod_auth_openidc
URL Redirection to Untrusted Site ('Open Redirect') in mod_auth_openidc
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
GitHub_M: GitHub_M
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Re
Red Hat
mod_auth_openidc: open redirect due to target_link_uri parameter not validated
vendor_redhat·2021-09-03·CVSS 4.7
CVE-2021-39191 [MEDIUM] CWE-601 mod_auth_openidc: open redirect due to target_link_uri parameter not validated
mod_auth_openidc: open redirect due to target_link_uri parameter not validated
mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.
A open redirect flaw was found in mod_auth_openidc where it does not sanitize target_link_uri paramater pro
Debian
CVE-2021-39191: libapache2-mod-auth-openidc - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HT...
vendor_debian·2021·CVSS 4.7
CVE-2021-39191 [MEDIUM] CVE-2021-39191: libapache2-mod-auth-openidc - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HT...
mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.
Scope: local
bookworm: resolved (fixed in 2.4.9.4-1)
bullseye: resolved (fixed in 2.4.9.4-0+deb11u1)
forky: resolved (fixed in 2.4.9.4-1)
sid: resolved (fixed in 2.4.9.4-1)
trixie: resolve
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6a433e5dd8e2b3dhttps://github.com/zmartzone/mod_auth_openidc/issues/672https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9.4https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-2pgf-8h6h-gqg2https://lists.debian.org/debian-lts-announce/2023/07/msg00020.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/32RGPW5LZDLDTB7MKZIGAHPSLFOUNWR5/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RHXO4O4G2UQS7X6OQJCVZKHZAQ7SAIFB/https://github.com/zmartzone/mod_auth_openidc/commit/03e6bfb446f4e3f27c003d30d6a433e5dd8e2b3dhttps://github.com/zmartzone/mod_auth_openidc/issues/672https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9.4https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-2pgf-8h6h-gqg2https://lists.debian.org/debian-lts-announce/2023/07/msg00020.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/32RGPW5LZDLDTB7MKZIGAHPSLFOUNWR5/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RHXO4O4G2UQS7X6OQJCVZKHZAQ7SAIFB/
2021-09-03
Published